Plaque, a buildup of low-density lipoprotein (the so-called "bad" cholesterol), white blood cells, calcium and debris on the inside of the arteries, can lead to heart attack and stroke. Omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) may help reverse plaque buildup in the arteries and reduce the risk of heart disease.
The omega-3 fatty acids in fish oil have anti-inflammatory effects as well as the ability to reduce platelet aggregation, the ability of platelets to stick together. Inflammation damages the inside of the artery walls, which encourages the formation of blood clots to heal the damage. Fish oil also acts as a blood thinner and dilates bloods vessels. Fish oil can also reduce levels of triglycerides, the form of fat stored in your body, as well as LDL. Taking fish oil also improves your intake ratio of omega-3 fatty acids to omega-6 fatty acids, a ratio that should be around 1:5 but is actually around 1:17 in the average American diet, according to the University of Minnesota.
The various actions of fish oil work together to decrease or reduce plaque formation and the risk of heart disease. Fish oil reduces the amount of LDL available to build up as plaque. Decreasing inflammation on the blood vessel walls decreases the number of platelets that congregate at the site to repair it, which in turn reduces the risk of clot formation. Clots can break off and lodge in arteries, reducing blood flow to the heart, causing heart attack, or to the brain, causing stroke. Dilated bloods vessels have less of a chance of total blockage from plaque. Improving your omega-3 to omega-6 fatty acid ratio increases prostacyclin, which reduces platelet activity and decreases arterial spasms, and decreases thromboxanem, which has the opposite effect.
Researchers from the University of Southampton assessed the effects of sunflower oil or placebo compared to fish oil on plaque formation in patients with existing carotid artery plaque. Patients were waiting to undergo carotid endarectomy, a procedure to remove plaque from the carotid arteries. The study, published in the February 2003 issue of "The Lancet," found that patients taking fish oil had reduced inflammation at plaque sites and less likelihood of having a thin fibrous cap over plaque sites, which increases the risk of plaque rupture. Plaque rupture increases clot formation as white blood cells and platelets rush to the site to heal it.
Increasing your dietary fish intake of fatty fish such as salmon to twice a week increases your omega-3 fatty acid intake. To have an effect on plaque, your doctor may also recommend taking between 1 and 4 g of fish oil per day. Do not take more than 1 g per day without talking with your doctor first, especially if you take blood thinners or have diabetes. Fish oil can potentiate the actions of blood thinners, possibly causing excessive bleeding.